This invention relates generally to the field of thermal protection for components operating in a high temperature environment. More particularly, this invention relates to the fabrication of a cooling feature on the surface of a component substrate. This invention has specific application to the fabrication of a cooling feature on a curved surface of a combustion turbine hot section component.
Combustion turbine engines generate combustion gases having temperatures that can exceed the allowable operating temperature of metals used to manufacture component parts of the turbine. Many cooling schemes are known for protecting such components, for example, the use of a film of cooling fluid and/or the application of an insulating material over the heated surface. It is also known to form a cooling feature integral to a component for conducting a cooling fluid through confined cooling channels near the component surface. Such cooling features may be formed by a casting process, or they may be machined into the part. However, it is difficult to form the cooling fluid channels of such cooling features to be close to the heated surface, since manufacturing tolerances must be accommodated in order to avoid an unintended break-through of the cooling channel through the component wall. Furthermore, the geometry of such cooling features is necessarily limited by the available casting and machining technologies, as well as manufacturing cost restrictions.
It is also known to apply a cooling panel to the surface of a portion of a gas turbine member to define a cooling flow channel through which a cooling fluid can travel to cool the turbine member. U.S. Pat. No. 6,018,950 issued on Feb. 1, 2000, to Scott Michael Moeller and assigned to Siemens Westinghouse Power Corporation describes one such cooling panel design. The cooling panel of the ""950 patent is formed by using a corrugated metal member. The corrugations form channels through which a cooling gas may be circulated over the surface of the turbine member. The cooling gas serves to insulate the underlying substrate and to move heat energy away from the substrate material. A stamping process is used to form the corrugations in the metal member. The metal member is then attached to the turbine member by filet and spot welding. Such cooling panels may be used successfully on static portions of a combustion turbine. However, such panels would not be applicable for use on rotating members such as turbine blades, since the stresses exerted on such a member would increase the risk of mechanical failure of the weld joint between the panel and the underlying substrate. Furthermore, such panels would be difficult to apply to a curved surface.
It is also known to form a cooling feature on the surface of a substrate to provide channels for the passage of a cooling fluid over the substrate surface. One such device is described in an article by Kevin W. Kelly published in 1999 by The Minerals, Metals and Materials Society, Elevated Temperature Coatings, Science and Technology III, and titled xe2x80x9cHigh Aspect Ratio Microstructure-Supported Shroud for a Turbine Blade.xe2x80x9d The micro heat exchanger is formed by electro-depositing an array of microstructures on a substrate surface, then affixing a metal shroud on top of the microstructures. Cooling passages defined by the spaces between the microstructures and below the shroud form cooling passages for conducting a cooling fluid over the substrate surface. The microstructures are formed by electro-plating a metal through holes formed in a sheet of polymer material that is applied to the surface of the substrate. The shroud is held in position over the microstructures by a shrink fit. The pattern of holes is formed in the polymer material by an X-ray lithography process. While this process is useful for a curved surface, it is limited in its commercial application by the cost of the X-ray lithography process and the difficulty of applying the sheet of polymer to the substrate. Furthermore, the attachment of a shroud to the microstructures with a mechanical shrink fit joint may be unacceptable for the environment of a rotating turbine blade.
Accordingly, an improved process and device for forming cooling features on a turbine component is needed.
A method of manufacturing a component is described herein as including: providing a substrate material having a surface; coating the substrate material surface with a layer of masking material; removing portions of the masking material by directing laser energy toward the masking material, a remaining portion of the masking material defining a pattern of voids wherein the substrate surface is exposed; electroplating a support material onto the exposed substrate surface within the voids to form a plurality of supports; electroplating a skin material onto the supports and over the remaining portion of the masking material to form a skin interconnecting the supports; and removing the remaining portions of the masking material to form cooling channels defined by the substrate surface, the supports and the skin. The skin material and the support material may be selected to be two different materials, and a layer of insulating material may be deposited on a top surface of the skin.
A method of manufacturing a component is further described herein as including: providing a substrate material having a surface; coating the substrate surface with a layer of masking material; removing portions of the masking material by directing laser energy toward the masking material, a remaining portion of the masking material defining a pattern of voids wherein the substrate surface is exposed; electroplating a support material onto the exposed substrate surface within the voids to form a plurality of supports; removing the remaining portions of the masking material; and bonding a skin member to the plurality of supports to form a plurality of cooling channels defined by the substrate surface, the supports and the skin member.
A method of manufacturing a component is further described herein as including: providing a substrate material having a surface; providing a skin member having a surface; coating the skin member surface with a layer of masking material; removing portions of the masking material by directing laser energy toward the masking material, a remaining portion of the masking material defining a pattern of voids wherein the skin member surface is exposed; electroplating a support material onto the exposed skin member surface within the voids to form a plurality of supports; removing the remaining portions of the masking material; and bonding the plurality of supports to the substrate surface to form a plurality of cooling channels defined by the substrate surface, the supports and the skin member.
A method of manufacturing a component is further described as including: providing a substrate having a surface; providing a skin member having a surface; coating the skin member surface with a layer of resin; removing portions of the masking material by directing laser energy toward the masking material, a remaining portion of the masking material defining a pattern of voids wherein the skin member surface is exposed; electroplating a support material onto the exposed skin member surface within the voids to form a plurality of supports; electroplating a base member material onto the supports and over the remaining portion of the masking material to form a base member interconnecting the supports; removing the remaining portions of the masking material to form cooling channels defined by the skin member surface, the supports and the base member; and bonding the base member to the substrate surface.
A combustion turbine component is described herein as including: a substrate material; a bond coat material disposed over a surface of the substrate material; an insulating material disposed over the bond coat material; and a cooling channel formed through the bond coat material for the passage of a cooling fluid over the surface of the substrate material and below the surface of the ceramic insulating material.
A combustion turbine component is further described as including: a substrate material; a plurality of supports formed of a support material joined to a surface of the substrate material by a diffusion bond; a skin formed of a skin material joined to the plurality of supports opposed the substrate material by a diffusion bond; the substrate material, supports and skin defining a plurality of cooling channels for the passage of a cooling fluid proximate the substrate material; wherein the support material and the skin material have different properties.